The panel, which was convened at the request of the Drug Enforcement Agency (DEA), was tasked with evaluating DXM's potential for abuse as well as the drug industry's ability to control or prevent such abuse, particularly among teenagers seeking a cheap, easily accessible high.
The FDA usually follows the advice of its advisory panels, though it is not required to do so.
Taken in very high doses, cough medicines which contain DXM, such Robitussin DM and Tylenol Cough, can cause euphoria and hallucinations. Such highs -- known as robotripping -- have resulted in an increasing number of emergency room visits over the past several years. In 2008, DXM abuse led to 8,000 trips to the ER. That's a 72% increase over four years, according to DEA documents.
Despite the rise in numbers, the Drug Safety and Risk Management Advisory Committee concluded that the risks did not warrant restricting DXM under the Controlled Substances Act.
Had the 15-9 vote gone otherwise, the vast majority of cough medicines would likely have been given Schedule V status. Though it is the least restrictive level in a tiered system used by the DEA to classify dangerous drugs, Schedule V medications can only be sold at a pharmacy, not at convenience stores or supermarkets.
In practice, such scheduling can be even more restrictive. "Many pharmacies don't carry schedule V drugs, especially in poorer neighborhoods," said panelist Janet Engle, professor and head of the department of pharmacy practice at the University of Illinois at Chicago.
The Consumer Healthcare Products Association (CHPA), a trade group representing cough syrup manufactures, argued that cough medicines had a very low potential for abuse. Teenagers, said one CHPA spokesperson, consider them a "lousy high" and a drug of choice only among "losers."
Helping to spread that impression among teenagers is one part of the CHPA's strategy to discourage abuse. "The drug 'unsells' itself," according to a presentation by Linda Suydam, DPA, president of the CHPA.
The CHPA also urged the federal government to pass laws currently before Congress that would introduce tighter restrictions on bulk sales of DXM as well as prohibiting the sale of cough medicines containing DXM to anyone under the age of 18.
"The greatest potential [for preventing abuse] is in age limits," said panelist Leslie Hendeles, PharmD, a professor of pharmacy and pediatrics at the University of Florida Health Science Center.